Plugins: soft_run user_run

The next two RegRipper plugins I wanted to highlight are: soft_run and user_run. Some may have been familiar with what these plugins did and the registry keys they checked. I’m referencing the past tense since Harlan has been busy working and he updated these plugins in the process. Not only were new run keys added to the plugins but Wow6432Node keys were added as well. The registry run keys are locations on a system which automatically start programs. Run keys are present in the Software registry hives which start programs when the operating system starts. Run keys are also present in the NTUSER.DAT hives and these execute programs when the user logs onto the system. These plugins are demonstrated against registry hives from a system infected with Symantec detection W32.SillyFDC (MD5 78c9d2949c81984414e6e1f5974905e1).

soft_run plugin

The soft_run plugin parses the run keys located in the Software hive. The following are the keys checked:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
HKLM\Software\ Microsoft\Windows\CurrentVersion\RunServices
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Terminal
       Server\Install\Software\Microsoft\Windows\CurrentVersion\Runonce
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Terminal
       Server\Install\Software\Microsoft\Windows\CurrentVersion\Run

Windows performs Win32 emulation on 64-bit operating systems to make 32-bit applications work. Part of the emulation is registry redirection. 32-bit applications are redirected to HKLM\Software\Wow6432Node when they try to access HKLM\Software. The additional Wow6432Node run keys parsed by the soft_run plugin are:

HKLM\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Run
HKLM\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
HKLM\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\RunOnce

Running the soft_run plugin against the Software hive from the infected system produced the output below. In the output you will notice an entry for C:\Users\lab\Templates\cache\SFCsrvc.pif listed beneath a Wow6432Node. This malware entry provides us with a few different clues. First the malware obtained administrative privileges since a system-wide modification was made. The second was the malware was 32-bit executed on a 64-bit system.

soft_run v.20130329
(Software) [Autostart] Get autostart key contents from Software hive

Microsoft\Windows\CurrentVersion\Run
LastWrite Time Thu Apr 4 17:36:00 2013 (UTC)
VMware User Process - "C:\Program Files\VMware\VMware Tools\vmtoolsd.exe" -n vmusr

Microsoft\Windows\CurrentVersion\Run has no subkeys.

Microsoft\Windows\CurrentVersion\RunOnce
LastWrite Time Thu Apr 4 17:34:33 2013 (UTC)
Microsoft\Windows\CurrentVersion\RunOnce has no values.
Microsoft\Windows\CurrentVersion\RunOnce has no subkeys.

Microsoft\Windows\CurrentVersion\RunServices not found.

Wow6432Node\Microsoft\Windows\CurrentVersion\Run
LastWrite Time Thu Apr 4 18:48:45 2013 (UTC)
HotKey - C:\Users\lab\Templates\cache\SFCsrvc.pif
User Agent - C:\Windows\SysWOW64\fdisk.com

Wow6432Node\Microsoft\Windows\CurrentVersion\Run has no subkeys.

Wow6432Node\Microsoft\Windows\CurrentVersion\RunOnce
LastWrite Time Tue Jul 14 04:53:25 2009 (UTC)
Wow6432Node\Microsoft\Windows\CurrentVersion\RunOnce has no values.
Wow6432Node\Microsoft\Windows\CurrentVersion\RunOnce has no subkeys.

Microsoft\Windows\CurrentVersion\Policies\Explorer\Run not found.

Wow6432Node\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run not found.

Microsoft\Windows NT\CurrentVersion\Terminal Server\Install\Software\Microsoft\Windows\CurrentVersion\Run not found.

Microsoft\Windows NT\CurrentVersion\Terminal Server\Install\Software\Microsoft\Windows\CurrentVersion\RunOnce not found.

user_run plugin

The user_run plugin parses the run keys located in the NTUSER.DAT hive. The following are the keys checked:

HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows\Run
HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
HKCU\Software\Microsoft\Windows\CurrentVersion\Run
HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKCU\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Terminal
       Server\Install\Software\Microsoft\Windows\CurrentVersion\Runonce
HKCU\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Terminal
       Server\Install\Software\Microsoft\Windows\CurrentVersion\Run
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServicesOnce
Run value listed in HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows

Similar to the soft_run plugin, user_run also takes into account Win32 emulation on 64-bit operating systems. The additional Wow6432Node run keys parsed are:

HKCU\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Run
HKCU\Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run

Running the user_run plugin against the Software hive from the infected system produced the output below. In the output notice the entries for C:\Users\lab\Templates\cache\SFCsrvc.pif and C:\Users\lab\AppData\Local\Temp\svchost.com. The biggest clue provided by the output is the lab user account should be focused on to determine the initial infecton vector.

user_run v.20130329
(NTUSER.DAT) [Autostart] Get autostart key contents from NTUSER.DAT hive

Software\Microsoft\Windows\CurrentVersion\Run
LastWrite Time Thu Apr 4 18:48:45 2013 (UTC)
HotKey: C:\Users\lab\Templates\cache\SFCsrvc.pif
User Agent: C:\Users\lab\AppData\Local\Temp\svchost.com

Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Run not found.

Software\Microsoft\Windows\CurrentVersion\RunOnce
LastWrite Time Thu Apr 4 17:35:09 2013 (UTC)

Software\Microsoft\Windows\CurrentVersion\RunOnce has no values.

Software\Microsoft\Windows\CurrentVersion\RunServices not found.

Software\Microsoft\Windows\CurrentVersion\RunServicesOnce not found.

Software\Microsoft\Windows NT\CurrentVersion\Terminal Server\Install\Software\Microsoft\Windows\CurrentVersion\Run not found.

Software\Microsoft\Windows NT\CurrentVersion\Terminal Server\Install\Software\Microsoft\Windows\CurrentVersion\RunOnce not found.

Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run not found.

Software\Wow6432Node\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run not found.

Software\Microsoft\Windows NT\CurrentVersion\Windows
LastWrite Time Thu Apr 4 18:48:46 2013 (UTC)
Run value = C:\Users\lab\AppData\Local\Temp\svchost.com
run value = C:\Users\lab\AppData\Local\Temp\svchost.com
load value = C:\Users\lab\AppData\Local\Temp\svchost.com